Slow cooker

ABSTRACT

A slow cooking appliance device. The device including: a body having a base, the body receives within it a removable cooking vessel; a movable heating element supported by the base; and a lift mechanism within the base for raising and lowering the movable heating element, such that the heating element is movable between an upper position and a lowered position.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/308,760, filed Dec. 10, 2018, which is a 371 National StageApplication of PCT Application No. PCT/AU17/50565, filed Jun. 7, 20217,which claims the benefit of Australian Application No. 2016902233, filedJun. 8, 2016, the disclosures of which are incorporated herein byreference in their entireties.

FIELD OF THE INVENTION

The invention relates to slow cookers and more particularly to anelectric slow cooker that is also able to sear foods.

BACKGROUND OF THE INVENTION

Electrical slow cookers are well known. Slow cookers with searingfunctionality are also known. However, conventional searing slow cookersutilise two distinct heating elements. A lower heating element is usedprimarily for high temperature searing and a second heating elementsurrounds the cooking vessel and is used during slow cooking. Thepresent invention seeks to simplify and improve the performance ofsearing slow cookers by providing only a single heating element togetherwith (optionally) an improved user interface. In addition, the inventionseeks to provide cooking methods or modes that best utilise the novelmechanical and electro-mechanical features that the invention provides.

SUMMARY OF THE TECHNOLOGY

The present technology provides a slow cooker with searingfunctionality.

According to an aspect of the technology, there is provided a slowcooking appliance device, the device including: a body having a base,the body receives within it a removable cooking vessel; a movableheating element supported by the base; and a lift mechanism within thebase for raising and lowering the movable heating element, such that theheating element is movable between an upper position and a loweredposition.

Preferably, when the movable heating element is in the upper position,the movable heating element is substantially conductively thermallycoupled to the removable cooking vessel. More preferably, when themovable heating element is in the lowered position, the movable heatingelement defines a gap such that the removable cooking vessel issubstantially heated by the movable heating element through a process ofconvection heating.

Preferably, the lift mechanism uses a jack screw assembly to raise andlower the movable heating element.

Preferably, the lift mechanism is operated by a motor that is controlledby a processor for raising and lowering the movable heating element.

Alternatively, the lift mechanism may also be manually operated by amovable lever that acts to raise and lower the movable heating element.Preferably, an upper surface of the movable heating elementsubstantially conforms to an underside of the vessel for enablingconductive heating there between.

Preferably, the removable cooking vessel has a floor and a side wall,and an underside of the vessel floor defines a circumferential groove.

The device preferably includes a liner located within the body forreceiving the removable cooking vessel.

Preferably, the liner is carried by the movable heating element. Morepreferably, the liner travels up and down with the movable heatingelement and makes sliding contact with a collar that is supported by thebody.

Preferably, the liner extends from an upper rim of the body to alocation below the movable heating element; the liner has an internalrim that defines a central opening through which extends the liftmechanism. More preferably, the liner defines a lower internalcircumferential trough for capturing debris that falls between thevessel and the liner. The liner may also preferably carry a drain tubethat is located about a low point of the trough for carrying fluids fromthe trough.

Preferably, the liner is supported by the body and substantiallyconfirms to the removable vessel, and the movable heating element andthe lift mechanism are located beneath the liner such that the heatingelement contacts an underside of the liner when in the upper position.

The device preferably includes a temperature sensor that is in thermalcommunication with the vessel. Preferably, a sensor plate carries thetemperature sensor, and the sensor plate is adapted to make thermalcontact with the lower surface of the vessel floor. More preferably, thetemperature sensor transmits a temperature signal to a processor forregulating a cooking processes. The temperature sensor may be locatedabove an electric fan.

Preferably, the liner has vents, and the device further includes anelectric fan that causes air flow through the vents and about theheating element.

The device preferably includes an electric fan that assist convectionheat transfer from the heating element.

According to an aspect of the technology, there is provided a slowcooking appliance device, the device including: a removable cookingvessel; a body having a base; a liner located within the body forreceiving the removable cooking vessel; a vertically movable heatingelement supported by the base; and a lift mechanism within the base forraising and lowering the movable heating element, such that the heatingelement has an upper position in which it is substantially conductivelythermally coupled to an underside of the vessel and a lowered positionin which a gap is formed between the movable heating element and theunderside of the vessel.

Preferably, the device further includes an electric fan that assistsconvection heat transfer from the heating element by circulating airabout the heating element.

Preferably, the device further includes a temperature sensor that is inthermal contact with the vessel.

The liner preferably defines a lower internal circumferential trough forcapturing debris that falls between the vessel and the liner.

According to an aspect of the technology, there is provided a slowcooking appliance device including: a body that receives within it aremovable cooking vessel; the base supporting a vertically movableheating element; the movable heating element having an upper position inwhich it is in conductive thermal contact with an underside of thevessel and a lowered position in which a gap is formed between themovable heating element and the underside; and a mechanism within thebase for raising and lowering the movable heating element.

Accordingly, there is provided an electrical slow cooker with searingfunctionality having a removable cooking vessel under which is located aheating plate that is removable between two cooking position limits.

In some embodiments of the invention, the heating plate is moved by amotor in response to a user input from the user interface.

In other embodiments of the technology, the heating plate is manuallyadjusted between the two distinct position limits.

There is also provided a searing slow cooker having a single heatingelement located below a removable cooking vessel.

In preferred embodiments of the technology, the side walls of thecooking vessel and the interior side walls of the base that supports thecooking vessel define a generally cylindrical flow path or chamber forhot air.

In other embodiments of the invention, the interior side wall of thedevice moves in unison with the heating element.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

In order that the invention be better understood, reference is now madeto the following drawing figures in which:

FIG. 1 is a cross sectional view of a slow cooker with searingfunctionality;

FIG. 2 is a cross section of the device depicted in FIG. 1 , where the

heating plate and the heating elements have been lowered into

a slow cooking orientation;

FIG. 3 is a perspective view of the outer ring and synchronous motordepicted in FIG. 1 and FIG. 2 ;

FIG. 4 is a perspective view illustrating the stabilising rods andprotective ring;

FIG. 5 is a cross sectional view illustrating a heating plate with dualheating elements;

FIG. 6 is a cross section of an alternate embodiment where heated air isrecirculated by the device's fan;

FIG. 7 is an underside perspective view of the heating plate depicted inFIG. 6 ;

FIG. 8 is an underside perspective view of the heating plate depicted inFIG. 6 ;

FIG. 9 is cross sectional view of a slow cooker with searingfunctionality illustrating the location of the thermal sensor and itsmetallic cap;

FIG. 10 is a cross-sectional schematic view of a motor and fan assemblywherein hollow shafting allows the temperature sensor's electrical leadto pass through the fan shaft and motor;

FIG. 11 is a cross-sectional view of an embodiment having vents in theliner and a fan that blows air through the vents;

FIG. 12 is a cross-sectional view of an embodiment where the cookingvessel rather than the heating plate can move vertically up and down;

FIG. 13 is a cross-sectional view of an embodiment where the cookingvessel rather than the heating plate can move vertically up and down;

FIG. 14 is a flow chart suggesting modes of operation for the devicesdisclosed in the specification;

FIG. 14 a is a cross sectional view illustrating a presence switch fordetecting a cooking vessel;

FIG. 15 is a front elevation of a slow cooker with searing functionalityhaving a manual rather than motorised adjustment of the heating plate orvessel;

FIG. 16 is a perspective view of the ramp disc and heating platesuggested by FIG. 15 ;

FIG. 17 is a cross-sectional view of a heating plate supported by a rampmechanism of the kind suggested by FIG. 16 ;

FIG. 28 is a perspective view of a ramp ring and manual slider;

FIG. 19 is a perspective view of a ramp ring and motorised adjustmentmechanism;

FIG. 20 is a cross-sectional view of a mechanism for raising andlowering a cooking vessel in a searing slow cooker, in a searingorientation;

FIG. 21 is a cross-sectional view of a mechanism for raising andlowering a cooking vessel in a searing slow cooker, in a slow cookingorientation;

FIG. 22 is a section view of an embodiment slow cooker according to thetechnology, which utilise a vertically adjustable heating element;

FIG. 23 is a section view of an embodiment slow cooker according to FIG.22 ;

FIG. 24 is a section view of an embodiment slow cooker according to FIG.22 ;

FIG. 25 is a section view of an embodiment slow cooker according to thetechnology, which utilise a vertically adjustable heating element; and

FIG. 26 is a section view of an embodiment slow cooker according to FIG.25 .

BEST MODES AND OTHER EMBODIMENTS OF THE TECHNOLOGY

As shown in FIG. 1 , an electrical slow cooker with searingfunctionality 100 comprises a body or base 101 that receives andsupports within it a removable cooking vessel 102. The base supports avertically movable heating plate 103. The heating plate 103 has, forexample, at least a single electrical heating element 104. The heatingplate and its heating element 103, 104 move from an uppermost or searingposition as shown in FIG. 1 to a fully lowered or slow cooking positionas will be explained. The heating plate and its heating element may alsoassume any position between the upper and lower limits of movement. Theheating plate is supported by posts 130 that connect it to a metal heatshield 131. In this example the shield 131 is attached to an actuator(as will be explained) by second post 112.

In the embodiment of FIG. 1 , the heating plate 103 has a centralopening 105 through which protrudes a sensor plate 106. The top of thesensor plate io6 is generally flush with the top of the heating plate103 when the heating plate is at its upper most or searing orientation.In some embodiments, the sensor plate and heating plate are adapted tomake contact with the lower surface of the vessel floor simultaneously.The sensor plate 106 carries a heat sensor such an NTC thermistor thattransmits temperature data to the device's electronic controller 107.Temperature data is used by the controller to regulate cooking processesor to provide an indication that the vessel has been removed, as isknown in the art. The sensor plate io6 supports or contacts theunderside 116 of the cooking vessel 102 and is stationary in thisexample. Below the sensor plate io6 is located a rotating electrical fan108 that is driven by the device's fan motor 109. An elongated shaft noconnects the motor 109 to the fan 108. The controller drives the fan 108to discharge a flow of air through a gap 111 or one or more openings 112located below the sensor plate 106 during slow cooking.

As further depicted in FIG. 1 , the cooking vessel 102 may have aperipheral groove or area of reduced thickness 113 formed around theperiphery of the floor, preferably on the underside of the floor. Theperipheral groove 113 is located adjacent to or radiantly outward of theouter edge 114 of the heating plate. The area of reduced thickness orgroove 113 limits the flow of heat to the sidewall 115 of the vesselduring searing, that is, when the heating plate 103 is in contact withthe underside of the vessel. In this example, the underside of thevessel's floor 116 is slightly concave and conforms to the slightlyconvex shape of the heating plate 103.

In preferred embodiments, the vessel 102 has an outwardly extendingflange or rim 117 that is supported above the upper most surface 118 ofthe base by a polymeric seal 119. The seal 119 prevents hot air fromescaping through the gap between the rim 117 and the upper surface 118.

In some embodiments, the sheet metal forming the upper surface 118 alsoforms an upper extent of the cavity 120 that receives the vessel. Thus afixed interior collar 121 is formed. In the example of FIG. 1 , theheating plate 103 carries an optional liner 122 that travels verticallyup and down with the heating plate 103. The upper portion 123 of theliner 122 makes sliding or surface contact with the collar 121 that itsurrounds. In this way hot air within the chamber 120 is inhibited fromentering the interior of the body.

As suggested by FIG. 2 , an actuator such as a jack screw mechanism 200is capable of translating the heating plate 103 and the liner 122 so asto separate the heating plate 103 from the underside 201 of the cookingvessel. In this example, the jack screw or actuator 200 comprises arotating outer rim 202 having external teeth that are driven by a piniongear 203. The pinion gear 203 is driven by an electric motor 204 that iscontrolled by the device's microprocessor or controller 107 a. Rotationof the outer ring 202 causes a co-operating and threaded inner ring 205to rise and lower relative to the base 101. The inner ring 205 carries(via second posts 206 or otherwise) a metal ring 207. The first posts208 interconnect the metal ring 207 to the underside of the heatingplate. The metal ring 207 acts as a heat sink and shield, protectingcomponents below the ring from heat generated by the heating element104. Thus, rotation of the pinion gear 203 causes the heating plate 103and the liner 122 to go up and down (reciprocate vertically). When theheating plate 103 is spaced away from the underside of the vessel, a gapX is formed between the vessel and the heating plate. The gap andchamber 120 communicate. In this way, the volume of the chamber 120increases as the heating plate and liner are lowered. Heated air(exclusively) heats the vessel during slow cooking operations. When inthe searing orientation, the heating plate heats primarily the floor ofthe vessel, whereas in the slow cooking orientation, hot air generatedby the heating plate heats both the underside of the vessel and the sidewall of the vessel. The generally cylindrical gap Y must be adequate forhot air to rise to a point adjacent to or just under the rim 117 of thevessel. Accordingly, the gap Y is from about 1 to 20 MM. The gap X ispreferably less than 5 omm.

As further shown in FIG. 2 , the shaft 110 that connects the fan motor109 to the centrifugal (or other) fan 108 passes through a cylindricalriser or sleeve 210 that directly or indirectly supports the sensorplate 106.

The upper edge 211 of the sleeve is above the upper surface of theheating plate 103 when the heating plate is in the lowermost or slowcooking orientation.

As shown in FIG. 3 , the outer ring 202 of the actuator 200 is supportedand restrained by curved retaining walls 300. A gap in the retainingwall 300 allows the rotating pinion gear 203 to make contact with teeth301 formed on an outer surface of the outer ring 202. The retainingwalls 300 carry flexible teeth or clips 302 that allow the outer ring202 to be easily installed and yet prevent the outer ring fromtranslating vertically. The clips 302 engage an upper rim 303 of theouter ring. The inner surface of the outer ring carries threads 304 thatco-operate with threads 305 formed on an outside surface of the innerring 205 as shown in FIG. 4 .

As shown in FIG. 4 , the vertical reciprocation of the heating plate 103and the metal ring 207 is stabilised by an array of telescopic supports401. Each support 401 comprises a lower and outer tube 402 that iscarried by the base. Rods 403 extend from the metal ring 207 to alocation within the tubes 401. The rods 403 may be polymeric to suppressheat transfer from the ring 207. A compression spring 404 supports therods 403 and minimises misalignment between the rods 403 and the tubes401. In preferred embodiments, there are a minimum of two and in thisexample three rods 403 spaced at 120 degrees.

It would be appreciated that the fan 108 is preferably programmable tooperate in slow cooking modes, that is, when the heating plate 103 islowered and forms a gap X with respect to the underside of the vessel.The controller 107 a causes the fan to operate to circulate air withinthe gap X and chamber 120 during slow cooking modes and preferablyceases operation of the fan during high temperature and searing modeswhen air cannot flow over the heating plate 103 into the chamber 120.

As suggested by FIG. 5 the heating plate 103 may carry one, two or moreheating elements 500, 501. Two separate heating elements allow thedevice to utilise higher wattages for searing. Supplying power to onlyone of the heating elements 500, 501 allows lower wattages for slowcooking whereas both can be activated for high temperature searing.

As shown in FIG. 6 , the moving liner 122 may have radially outward fromit, a second liner 600 (Further clarification). The second liner 600 isfixed and isolates the air chamber 120 from the interior of the base. Inthis embodiment, the collar 121 has vents 601 that are exposed as theliner 122 descends. Hot air, particularly when propelled by the fan 108,rises in the chamber 602, passes through the vents 6oi and descendsbetween the liner 122 and the second liner 600. Previously heated airdescends 603 and is collected in a plenum 604 located below the fan 108.The fan 108 draws and recycles previously heated air during slow cookingfunctions. As shown in FIG. 7 and FIG. 8 , the underside of the heatingplate 610 may be provided with one or more rays of radially extendingfins 700, 701 which help to disperse hot air from the heater plate intothe chamber 120. In the example of FIG. 7 , two concentric arrays areprovided 700, 701. There are more radial fins in the inner array 700than in the outer array 701. Note that in this example, the heatingplate 610 lacks a central opening. As shown in FIG. 8 , the ribs in oneor both arrays may be curved 800.

In preferred embodiments of the invention, a thermal sensor is requiredto detect the temperature of the cooking vessel and transmit arepresentative signal to the device's controller 107 a. Although atemperature sensor for such a purpose may be located in variouspositions and may be of various types. In the example of FIG. 9 an NTCtemperature sensor 900 is located above the fan 901. It may be retainedby or protected by a thermally conductive plate such as a sheet metalplate 902 that is friction fit to the fan's housing 903.

Another example of a temperature sensor mounting is depicted in FIG. 10. In this example, an NTC thermistor 1000 is mounted above the fan 1001.The NTC thermistor woo may be mounted above or recessed into the fanhousing 1002. As with the example of FIG. 9 , the NTC thermistor may becovered by a metallic plate 1003 that protects the NTC and acts as athermal distributor. It is adapted to make contact with the underside ofthe cooking vessel. In this example, the rotating shaft 1004 between themotor 1005 and the fan 1001 is hollow or tubular. The motor's centralshaft 1006 is also hollow or tubular and may be a continuation of thefan shaft 1004. Thus a continuous passage way is formed from the lowerend of the motor 1007 through to the fan's hollow central hub 1008. Thisallows a second tube 1009 to be located within the shafting 1004, 1006.In this way the NTC thermistor's electrical lead can pass through thefan's hollow hub 1010, through the shafting 1004, 1006 and thus throughthe motor. The lead 1011 is protected by the inner tube 1009 and neitherwears, nor rotates when the motor drives the fan.

In another embodiment, and as shown in FIG. 11 , the moveable liner 1100that is attached to the moveable heating plate 1101 as previouslydescribed is provided with vents 1102. The vents perforate the liner1100, preferably in the area close to the gap 1103 formed between theheating plate 1101 and the underside of the cooking vessel 1104. Air isblown into the gap and chamber area 1105 by an electric fan 1106. Inthis example, the electric fan is located in the space between the liner1100 and the outside wall 1107 of the base. The air 1105 propelled bythe fan turbulates the air in the gap and chamber, distributing the hotair evenly around the cooking vessel 1108.

An alternative embodiment is disclosed with reference to FIG. 12 andFIG. 13 . In this embodiment, rather than moving the heating plate andits heating elements, the cooking vessel is reciprocated relative to theheating plate by the housing that also contains the fan and thetemperature sensor. Thus, as illustrated in FIG. 12 , the fan 1200 andits housing 1201 and the fan's motor 1202 move together, in unison,under the influence of the actuator 1203. In this example, the actuatoris essentially the same as the one depicted in (for example) FIG. 1through FIG. 4 . That is, an outer threaded ring 1204 is rotated by amotor and pinion gear 1205 relative to a non-rotating inner ring havingexterior threads 1206. To stabilise it, the inner ring may be providedwith any number of vertical stabilising rods 1207 that are receivedwithin co-operating cylinders 1208. A compression spring 1209 within thecylinder and below the rod counteracts the weight carried by the fanhousing 1201 owing to the cooking vessel and its contents. In FIG. 12 ,the fan housing and temperature sensor are shown in a lower most orsearing orientation. In FIG. 13 , the inner ring 1206 has been elevated.This causes the cooking vessel to rise vertically so as to create a gap1300 between the underside of the cooking vessel and the top of theheating plate. Note that whether it is the heating plate or the cookingvessel that moves vertically up and down, the temperature sensor remainsessentially in contact with the underside of the vessel at all times andduring all cooking operations. The springs also help prevent the rodsfrom jamming inside the cylinders.

As shown in FIG. 14 , a slow cooker with searing functionality asdescribed in the preceding drawing figures and text may communicatewith, provide notifications to or be controlled by a remote device suchas a computer, remote controller or mobile telephone 1401. The cooker1400 may be provided with electronic circuitry 1402 required to performthe aforesaid functions over a wireless or WIFI network 1403, aBluetooth wireless connection 1404 or utilising a hard wired connectionsuch as a USB or other network cable 1405. In preferred embodiments, thedevice 1400 has a single user control comprising a rotating dial with apush button switching functionality 1406. A display screen such as anLCD or TFT display 1407 is also provided. When power to the device 1400is first supplied, 1408 the display 1407 switches on and an audible beepis provided by a sound emitting device 1409 located in the base of thecooker. Initially, the display 1407 provides graphic or textual choicesto the user so that the user may use the select/confirm knob 1406 toselect between a slow cook mode and a sear mode 1410. Selection byrotation of the knob and subsequent confirmation (by pressing the knobor other predefined user input) of the slow cook mode 1411 results inthe graphic display 1407 providing, for example, a list or scrollablelist of food types 1412. In this example, the selectable food types aremeat, pork, chicken, soup, stew and beans. The selection of the foodtype relates to the cooking temperature or cooking time or both ofthese. In addition or subsequently, the display can also provide theuser with a means of selecting either an exact time or time ranges suchas low, medium and high cooking times defined as the time between whenthe cooking cycle is initiated and when the cooking process ends 1413.Once the food type and time have been input using the select/confirmuser input 1406 the cooking process is initiated by pressing theselect/confirm controller 1406 or a separate “start” button 1414.

After the start or confirm button has been activated by the user, thedisplay 1407 provides a graphic or textual display 1415 that includesthe mode (slow cook or sear), the selected food type 1412 and thetemperature of the food cooking as measured by the temperature sensorand interpreted by the device's processor. If the cooking vessel isremoved during a searing operation, the absence of the vessel is sensedby a switch or sensor located under the vessel, for example thetemperature sensor woo or switch 1451. If the vessel is not returned toits proper location relative to the vessel presence sensor within apre-set interval of, for example, 3-10 seconds, the controller willcause the heating elements to switch off and the display to return tothe previous display settings 1412, 1413. After a searing operation hascommenced 1415, the user may, in accordance with display information1407, switch to the slow cook mode. Thereafter, the display willindicate that the slow cook mode is in effect and will also show thefood type and time information such as elapsed cooking time or timeremaining or that time is being automatically controlled 1417. If thedevice is in a searing mode and the user switches the device to a slowcooking mode a series of events 1418 are initiated by the controller.Power is supplied to the synchronous motor 204 that drives the piniongear 203. The heating plate begins to lower, for example from theposition shown in FIG. 1 to the position shown in FIG. 2 . The heatingplate will stop either automatically or at a user selected depth atwhich point the synchronous motor stops. The controller then regulatesthe heating elements to achieve the correct slow cooking temperature andat that time the air circulation fan e.g. 108 is initiated.

After the cooking process is completed, the controller, in conjunctionwith signals from the temperature sensor maintain the vessel and itscontents at a constant and warm temperature 1419. An audible beep andvisual information may be provided to alert the user that the cookingprocess has stopped. Preferably, the heating plate will (without userintervention) return to its upper most position (the sear mode). Thedisplay will provide information relating to selected settings, alsoproviding a graphic indication that the “keep warm” mode is still activeand also optionally providing an indication of the time elapsed sincethe end of the cooking process.

If the cooking vessel is removed from the base during a slow cook mode1420 the vessel presence sensor located beneath the vessel is activated.The controller responds by switching off the heating elements if thevessel is not returned to its position within a pre-determined time, say3-10 seconds. After this time, the heating plate will be returned to itsupper most position (sear mode) and the display will revert to itsprevious display of information 1412, 1413.

As shown in FIG. 14 a , a slow cooker with searing functionality 1450may incorporate a switch or sensor 1451 that communicates with thedevice's processor 107 a. In this example, an electrical switch 1451 ismounted in a through opening on an upper rim 1452 in a location belowthe rim of a cooking vessel 1453 when that vessel is fully installedwithin the cooker. In this example, the underside of the rim 1453contacts the switch 1451 and the switch transmits a signalrepresentative of the vessel's presence, by an electrical lead 1454 tothe device's controller or processor 107 a.

The searing and slow cooking functionality that has been previouslydiscussed is also achievable in an embodiment where the heating elementand its heating plate are adjustable manually rather than electrically.As suggested previously, the same mechanism that can raise and lower theheating plate may be also used to raise and lower a cooking vesselrelative to the stationary heating plate. A manually adjustable heatingplate and a searing slow cooker is disclosed, by way of example, in FIG.15 through FIG. 18 . In the example of FIG. 15 , the outer surface 1500of the base has a slot such a horizontal slot 1501 through whichprotrudes a mechanical handle or slider at 1502. FIG. 15 also suggeststhat the interface can be reduced in complexity with a provision of aselector knob having discreet rotational positions for differentregulated cooking temperature such as low, medium and high 1504. In thisexample an indicator light is provided for indicating when the “keepwarm” is enabled 1505. In this example, the slot and slider 1501, 1502are located symmetrically below the selection knob 1503.

As shown in FIG. 16 , the horizontally reciprocating slider 1502 isattached to a ramp disc 1601. The ramp disc comprises, for example,three spaced apart curved ramps 1602 that rotate about the device'svertical centre line in unison with the movement of the slider 1502.Each ramp is associated with a stationary saddle 1603 having an openingthrough which extends a lifting rod 1604. The lifting rod 1604 isstabilised and positioned by a cylindrical collar 1605 that is attachedto or supported by the saddle 1603.

The horizontal sliding movement of the heating plate vertical positionadjustment slider 1502 is limited by a pair of vertical posts orobstructions 1606, 1607. The position limits 1606, 1607 extend throughopenings 1608 in the ramp disc 1601 and establish the mechanical limitsof the range of motion of the slider 1502.

It can be seen at FIG. 16 that the ramp 1601 may have an inner ring 1610connected by radial spokes 1611 to an outer ring 1612 that carries theramps 1602. Openings 1608 between the inner and outer rings 1610, 1612accommodate the passage of the mechanical limits 1606, 1607.

As shown in FIG. 18 , the slider or slider handle 1502 may be formedseparately and attached to the ramp disc 1601. In the embodiment of FIG.18 it is attached to one of the spokes 1611 that interconnect the innerring 1610 with the outer ring 1612. In this example, there are threeramps 1602, each having a horizontal or flat spot 1801 corresponding tothe highest point of travel.

As suggested by FIG. 19 a ramp ring 1900 of the type generally disclosedabove may be rotated with, for example, a synchronous motor 1901 thatdrives a pinion gear 1902 that engages an arc shaped array of driventeeth 1903. The motor is operated by the device's controller 107 asimilarly to the synchronous motor 204 disclosed with reference to, forexample, FIG. 2 .

As shown in FIG. 17 , heat flow to the rods or posts 1604 is reduced byattaching them to a metal plate or heat shield 1701. The heat shield1701 is attached to the underside 1702 of the heating plate 1703 by aplurality of attachment posts 1704. Accordingly, the heating plate shownin FIG. 17 as well as the heating plates of a kind disclosed in FIG. 1through FIG. 4 can be adjusted vertically using a manual slider and rampassembly of the kind shown in FIG. 15 through FIG. 17 .

As shown in FIG. 20 , a slow cooker with searing functionality 2000 mayincorporate features for manually raising and lowering the cookingvessel 2001. In embodiments such as this, the heating plate is fixed orstationary. In this example, a locking and raising mechanism 2002 islocated on an upper rim 2003 of the base 2004. The mechanism 2002co-operates with a spade or arrow type pin 2005 located on an undersideof the outwardly directed rim 2006 of the cooking vessel 2001. In orderto keep the cooking vessel level, two, three or more pairs of mechanisms2002 and co-operating pins 2005 may be provided around the upper rim. Inthe example of FIG. 20 , a polymeric lock body 2007 is partiallyinserted into an opening 2008 on the upper rim 2003. The body has aperipheral shoulder 2009 that is maintained in position relative to theupper rim by two or more flexible retaining clips 2010 that flex oninstallation and thereafter engaged the rim of the opening through whichthe body 2002 is inserted. The lower part of the body comprises a cavityor holder 2011 for a compression spring 2012. The spring exerts anupward force on a flexible retaining head 2013. The retaining head 2013is attached to a shaft 2014 that captures the spring 2012. The upwardlimit of travel of the shaft 2014 and head 2013 is limited by a stopper2015 located on the shaft and external to the chamber 2011. Theretaining head 2013 has a central hub that supports, for example, anumber of flexible arms 2016. Each arm 2016 terminates in a bead or lip2017. The innermost tips of each lip 2017 define an opening throughwhich the enlarged head of the pin 2013 may pass when the head is in theuppermost or open position. The uppermost position is depicted in FIG.20 and represents the position of the cooking vessel during a slowcooking process.

As further shown in FIG. 20 , each pin 2005 comprises an enlarged head2018 that is adapted to be captured by the arms 2016 when the arms arebrought together, as will be explained. Also illustrated is a shoulderor release detail 2019 that is adapted to co-operate with the two ormore locking arms 2020 that are located above the flange 2009. Eachlocking arm 2020 has an undercut shoulder 2021 that allows each lockingarm to engage and trap the upper rim of the enlarged head 2018. In thisorientation, the cooking vessel 2001 is supported by the array ofmechanisms 2002 in an orientation where the bottom of the vessel 2001 isspaced above a preferably fixed heating plate, for example, the kindpreviously discussed.

As shown in FIG. 21 , the mechanism depicted in FIG. 20 can have a loweror locked position which is adapted to searing orientations. The vessel2001 cannot be removed in the lower position. In searing orientations,the bottom of the cooking vessel 2001 is preferably in direct contactwith a heating plate. As suggested by FIG. 21 , pressing the rim of thevessel towards the base traps the head 2018 of the pin 2013 with theretaining fingers 2016 this is because the flexible retaining fingers2016 are compressed by the locking fingers into an orientation where theretaining lips or beads 2017 trap the head 2018. The retaining fingers2016 are unable to open or expand and likewise, cannot move upward orrelease the pin because of the trapping effect of the undercuts 2021. Inthis orientation the spring 2012 is compressed. However, urging theupper rim downward or toward the base 2101 causes the shoulders 2005 tobear on and spread apart the chamfered upper portions 2102 of thelocking fingers so that the retaining fingers 2016 can be driven upwardby the spring 2012 and thus escape thereafter assuming the orientationdepicted in FIG. 20 .

The upper rim of the cooking vessel may be protected by a peripheralpolymeric (e.g. silicone rubber) heat insulating rim 2103. The rim has ahorizontal extent forming upper surface 2104 and a peripheral skirt 2105that preferably extends downwardly to at least partially protect theupper part of the mechanism. In some embodiments the lowest extent ofthe skirt 2106 extends lower than the upper rim 2003 of the base. Itwill be appreciated that the mechanism depicted in FIG. 20 and FIG. 21may be utilised in conjunction with practically any construction of slowcooker or cooking device where it is desirable to provide a cookingvessel 2001 with uniform vertical movement that facilitates upper andlower cooking positions, particularly searing and slow cookingpositions.

FIG. 22 through FIG. 26 illustrate embodiments of the technology thatutilise a vertically adjustable (or movable) heating element that makescontact with, or creates a gap between, itself and an underside of anadjacent vessel or liner that receives a vessel.

As shown in FIG. 22 , an embodiment slow cooker 2200 with searingfunctionality has a main body portion 2201. The upper end of the mainbody portion 2201 is terminated by an inwardly directly rim 2202. Inthis example, the rim 2202 is part of a rim assembly 2203. The rim 2202supports a fixed or removable liner 2204. The liner conforms to theshape of a cooking vessel 2205. The vessel 2205 has an outwardlydirected upper rim 2206. The underside of the vessel may also have acircumferential groove 2207, which is adjacent to its outer edge 2208.The groove limits heating of the vessel's sidewall 2209.

A vertically adjustable heating element 2210 is positioned within themain body and below the liner 2204. In this example, the heating element2211 is carried by a heat distribution plate 2212 whose upper surface2213 is shaped to conform to the underside of the vessel 2204. Theassembly 2214 that holds the heating element and heat distribution plateis carried by an actuator or jack screw mechanism 2215 that iscontrolled by the device's processor 2216. The processor transmits powerto an electric motor 2217. The motor 2217 drives the jack screwmechanism 2215, preferably through a reduction gear 2218.

With reference to earlier teaching of a mechanical means to reciprocatethe heating source, for example as shown in FIG. 15 through 18 , whilethe controller may remember or sense where the heating element ispositioned a user may be enabled or required to manually interact with amechanical actuator.

As shown in FIG. 23 , when inserted, the vessel 2300 fits snugly withinthe liner 2301. Thus, when the heating element 2302 is activated, hotair circulates within the internal compartment 2303, both under andaround the liner 2301.

As illustrated in FIG. 24 , instructions from the processor 2400 may betransmitted to the motor 2401 in response to a stored cooking program ora command input from a user. The motor and reduction gear cause the jackscrew 2402 to elevate the heating element and heat distribution plate2403 into surface contact with the underside of the liner 2404. In thisorientation, both the vessel 2405 and liner 2404 are heated byconduction rather than convection. This is the preferred orientation forsearing within the vessel 2405.

In the example of the FIG. 25 , the applicant has an internal liner 2500that extends from approximately the upper rim 2501 to a location 2502that is below the vertically adjustable heating element 2503 and heatdistribution plate 2504. The liner 2502 has an internal rim 2505 thatdefines a central opening through which extends the lifting mechanism orjack screw 2506. Because the rim 2505 is higher than the lowest point ofthe liner 2502, the lower part of the liner forms a circumferentialtrough 2507 that is able to capture debris that falls between the vessel2508 and the liner 2500.

In preferred embodiments, a low point of the trough 2507 carries a draintube 2509 that carries fluids away from the trough 2507. In thisexample, the vessel 2508 has a flat bottom 2510 and accordingly, theupper surface of the heat distribution plate 2611 is also flat. The jackscrew 2506 is able to raise and lower the heating element and heatdistribution plate without interfering with the liner 2500.

As shown in FIG. 26 , the jack screw or lifting mechanism 2506 haselevated the heating element and heat distribution plate 2601 intosurface contact with the underside of the cooking vessel 2602.

Although the invention has been described with reference to specificexamples, it will be appreciated by those skilled in the art that theinvention may be embodied in many other forms.

As used herein, unless otherwise specified, the use of the ordinaladjectives “first”, “second”, “third”, etc., to describe a commonobject, merely indicate that different instances of like objects arebeing referred to, and are not intended to imply that the objects sodescribed must be in a given sequence, either temporally, spatially, inranking, or in any other manner.

Reference throughout this specification to “one embodiment” or “anembodiment” or “example” means that a particular feature, structure orcharacteristic described in connection with the embodiment is includedin at least one embodiment of the present invention. Thus, appearancesof the phrases “in one embodiment” or “in an example” in various placesthroughout this specification are not necessarily all referring to thesame embodiment or example, but may. Furthermore, the particularfeatures, structures or characteristics may be combined in any suitablemanner, as would be apparent to one of ordinary skill in the art fromthis disclosure, in one or more embodiments.

Similarly, it should be appreciated that in the above description ofexemplary embodiments of the invention, various features of theinvention are sometimes grouped together in a single embodiment, figure,or description thereof for the purpose of streamlining the disclosureand aiding in the understanding of one or more of the various inventiveaspects. This method of disclosure, however, is not to be interpreted asreflecting an intention that the claimed invention requires morefeatures than are expressly recited in each claim. Rather, as thefollowing claims reflect, inventive aspects lie in less than allfeatures of a single foregoing disclosed embodiment. Any claimsfollowing the Detailed Description are hereby expressly incorporatedinto this Detailed Description, with each claim standing on its own as aseparate embodiment of this invention.

Unless specifically stated otherwise, as apparent from the followingdiscussions, it is appreciated that throughout the specificationdiscussions utilizing terms such as “processing,” “computing,”“calculating, “regulating” “determining” or the like, refer to theaction and/or processes of a microprocessor, controller or computingsystem, or similar electronic computing or signal processing device,that manipulates and/or transforms data.

Furthermore, while some embodiments described herein include some butnot other features included in other embodiments, combinations offeatures of different embodiments are meant to be within the scope ofthe invention, and form different embodiments, as would be understood bythose in the art. For example, in the following claims, any of theclaimed embodiments can be used in any combination.

Thus, while there has been described what are believed to be thepreferred embodiments of the invention, those skilled in the art willrecognize that other and further modifications may be made theretowithout departing from the scope of the invention, and it is intended toclaim all such changes and modifications as fall within the scope of theinvention.

While the present invention has been disclosed with reference toparticular details of construction, these should be understood as havingbeen provided by way of example and not as limitations to the scope ofthe invention.

What is claimed is:
 1. A slow cooking appliance device, the device including: a body having a base, the body receives within it a removable cooking vessel; a heating element supported by the base; a lift mechanism within the base for raising and lowering the removable cooking vessel, such that the cooking vessel is movable between an upper position, in which a gap is formed between the removable cooking vessel and the heating element, and a lowered position, in which the removable cooking vessel is substantially conductively thermally coupled to the heating element.
 2. The device according to claim 1, wherein, when the removable cooking vessel is in the upper position, a gap is created between the removable cooking vessel and the heating element such that the removable cooking vessel is substantially heated by the movable heating element through a process of convection heating.
 3. The device according to claim 2, wherein the gap is open to the environment.
 4. The device according to claim 1, wherein the device further includes a temperature sensor that is in thermal communication with the vessel.
 5. The device according to claim 4, wherein the temperature sensor is located above an electric fan.
 6. The device according to claim 1, wherein the device further includes an electric fan that assists convection heat transfer from the heating element.
 7. The device according to claim 1, wherein the lift mechanism further comprises: a first thread carried on an inner surface of an outer ring engaged with the base, and a second thread formed on an outside surface of an inner ring, the inner ring carrying the removable cooking vessel; and wherein the first thread and the second thread cooperate to move the removable cooking vessel between the upper position and the lowered position.
 8. The device according to claim 7, wherein the inner ring includes at least one stabilising rod.
 9. The device according to claim 8, wherein the stabilising rod is received within a co-operating cylinder.
 10. The device according to claim 9, wherein a spring within the cylinder counteracts the weight carried by the inner ring. 